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These were much longer in participants who had consistently high levels of physical activity than those who had sedentary lifestyles - as well as those who managed moderate amounts of exercise.

Prof Tucker, who specialises in exercise science, said despite their best efforts, no scientist has ever come close to stopping humans from aging. Even anti-aging creams can't stop Old Father Time.

But he says you may be able to slow cellular ageing - as long as you are willing to sweat. This could reduce the risk of age related illnesses including heart disease, cancer and dementia.

The study, published in the journal Preventive Medicine, said telomeres are our biological clock - and and are extremely tied with age.

Each time a cell replicates, we lose a tiny bit of these endcaps. So the older we get, the shorter our telomeres.

Prof Tucker found adults with high physical activity levels have telomeres with a biological aging advantage of nine years over those who are sedentary. They also had a seven year advantage compared to those who are moderately active.

He said: "If you want to see a real difference in slowing your biological aging, it appears that a little exercise won't cut it. You have to work out regularly at high levels."

Prof Tucker added: "We know that regular physical activity helps to reduce mortality and prolong life, and now we know part of that advantage may be due to the preservation of telomeres."

Other studies have showed short bursts of super intense exercise, such as cycling at full pelt for just four minutes, can reverse damage to cells

Earlier this year another US study showed short bursts of super intense exercise, such as cycling at full pelt for just four minutes, can reverse damage to cells.

The sessions, followed by three easier minutes, are needed 12 times a week, along with another 90 minutes walking on a treadmill.

High intensity interval training, as it is known, works better than longer cycling sessions and weightlifting to halt the damage to the cells' 'batteries' which may kickstart the ageing process, said the researchers.

Fixing defects in the DNA of these batteries, the mitochondria, is believed to help people live longer before falling ill with diseases of old age like heart failure and cancer.

High intensity interval training works to burn more fat by producing 'excess post-oxygen consumption'.

Four minutes cycling at close to maximum effort, before collapsing red-faced on the handlebars, leaves someone's resting metabolic rate elevated for longer after exercise.

The study found it works particularly well in causing cells to make more proteins for their energy-producing mitochondria. This ability is lost as people grow older.